VegSource Interactive, Inc. | Bill Harris, M.D.
I recently visited and looked at your data on breast cancer statistics for 33 countries. I could not make out the first graph. I was especially interested in the difference between Germany and the US. I had the opportunity to work in Germany for almost a year. While I was there, my premenopausal symptoms disappeared. I contributed it to the fact that Germany does not allow hormonally grown beef into the country. I was hoping to see a significant difference between Germany and the US which I did not. Any insights?
My first insight would be that eating hormone free beef is not really protective against breast cancer. To the extent that hormones contribute to breast cancer, beef is beef and will still contain the animal's own endogenous hormones. Some of the protein hormones are destroyed by digestion but the sterol hormones are not. It is possible that the decline in your menopausal symptoms was due to eating hormone-free beef, however menopausal symptoms decrease with time anyway so an important question would be whether they came back when you returned to the US.
The first graph at http://www.vegsource.com/harris/b_cancer.htm (and also at http://www.vegsource.com/harris/cancer_vegdiet.htm) indicates that animal source Calorie consumption has the highest correlation with breast cancer. In other words, the more animal source food one eats the higher the risk for breast cancer. The multiple regression table at the bottom of the breast cancer article indicates that of the dietary and environmental factors for which I was able to find data most of the other risk factors were also animal source nutrient intake of one kind or another.
The scientific literature is wildly conflicted on the subject of diet and breast cancer. I append an affirmative study, however I have 81 pages of references and some show just the opposite. In the absence of a final decision, game theory dictates the wisest choice.
If in fact diet is not a risk factor for breast cancer and one goes to a wholefood vegan diet anyway nothing has been lost since it's more than nutritionally adequate and offers other health, environmental, and ethical advantages.
If, on the other hand, one continues as an omnivore and the future final judgment is that diet really does affect breast cancer risk, then a serious error has been made.
-William Harris, M.D.
Abstract: In this prospective study, the relationship between energy acid fat consumption and the risk of breast cancer was examined. Between 1977 and 1983, 31,209 Norwegian women, 20 to 54 years of age attended a health screening. The attendees were given a food-frequency questionnaire to be completed at home, and this was returned by 25,892 (83%). During the 7 to 13 years of follow-up, 248 cases of breast cancer were identified for analysis by linkage to the Norwegian Cancer Registry. The relative risk of women who ate meat more than 5 times a week, as compared with those who consumed meat twice or less than twice a week, was 2.44. Consumers of 0.75 litres or more of full-fat milk daily had a relative risk of 2.91 compared with those who consumed 0.15 litres or less. A positive relationship was found between those reporting the highest quartile of monounsaturated fat consumption and the risk of breast cancer. The main foods contributing to the mono-unsaturated fat index were edible fats, meat and milk. (C) 1995 Wiley-Liss, Inc.